Ostrężnik Forest Nature Reserve is located near a settlement of the same name. Its area, established in 1960, is small - it is 4.1 hectares. The local limestone hills cover several caves (eg Ostrężnicka, Wierna, Wiercica), but these are not available for mass sightseeing. These caves were used by partisans during World War II. At the foot of the hills there are also periodic springs, or karst springs called Event Sources. The forest growing in the reserve consists mainly of beech and hornbeam stands.

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The mysterious and quite small ruins of the fortress, probably dating from the 14th century, are one of the least known defensive structures on the Cracow-Czestochowa Upland. It is assumed that the castle was erected on the initiative of Władysław Opolczyk, as one of the cells planned with the momentum of the defense system of the then Polish border. This structure may have a different genesis.

The outline of the object's walls has remained very weak. The layout of the castle, which was divided into upper, lower and lower partes, is currently poorly understood. On the south side you can see the remnants of the tower, which may have served as an entrance gate. It is not known when the castle was abandoned, anyway in the eighteenth and nineteenth centuries more and more ruined object was simply demolished.

Ostrężnik runs several tourist routes, among others. Eagles Nest Trail and the Jura Chain. The terrain can be found more closely, traversing it with a natural-didactic track "Trace of Mysteries" of 1.5 km.